KCL provides two distinct internal floating-point formats. One format is short; the other is single and serves also as double and long. The data types single-float , double-float , and long-float are considered to be identical, but short-float is distinct. An expression such as (eql 1.0s0 1.0d0) is false, but (eql 1.0f0 1.0d0) is true. Similarly, (typep 1.0L0 'short-float) is false, but (typep 1.0L0 'single-float) is true. For output purposes all floating-point numbers are assumed to be of short or single format.
The floating-point precisions are:
Format KCL/AOS KCL/VAX KCL/SUN KCL/UST ------------------------------------------------------ Short 24 bits 23 bits 24 bits 24 bits Single 56 bits 55 bits 53 bits 53 bits Double 56 bits 55 bits 53bits 53 bits Long 56 bits 55 bits 53 bits 53 bits
The floating-point exponent sizes are:
Format KCL/AOS KCL/VAX KCL/SUN KCL/UST ------------------------------------------------------ Short 7 bits 8 bits 8 bits 8 bits Single 7 bits 8 bits 11 bits 11 bits Double 7 bits 8 bits 11 bits 11 bits Long 7 bits 8 bits 11 bits 11 bits
There is no ``minus zero.'' (eql 0.0 -0.0) is true.
Common Lisp constants related to floating-point numbers have the following values in KCL.
most-positive-short-float
= - most-negative-short-float
= 7.237005s75 (KCL/AOS)
1.701412s38 (KCL/VAX)
3.402823s38 (KCL/SUN and KCL/UST)
least-positive-short-float
= - least-negative-short-float
= 5.397605s-79 (KCL/AOS)
2.938736s-39 (KCL/VAX)
1.401298s-45 (KCL/SUN and KCL/UST)
most-positive-long-float
= most-positive-double-float
= most-positive-single-float
= - most-negative-long-float
= - most-negative-double-float
= - most-negative-single-float
= 7.237005577332264f75 (KCL/AOS)
1.701411834604692f38 (KCL/VAX)
1.797693134862315f308 (KCL/SUN and KCL/UST)
least-positive-long-float
= least-positive-double-float
= least-positive-single-float
= - least-negative-long-float
= - least-negative-double-float
= - least-negative-single-float
= 5.397605346934027f-79 (KCL/AOS)
2.938735877055719f-39 (KCL/VAX)
4.940656458412469f-324 (KCL/SUN and KCL/UST)
short-float-epsilon
= 4.468372s-7 (KCL/AOS)
6.938894s-18 (KCL/VAX)
2.980232s-8 (KCL/SUN and KCL/UST)
short-float-negative-epsilon
= 2.980232s-8 (KCL/AOS)
6.938894s-18 (KCL/VAX)
2.980232s-8 (KCL/SUN and KCL/UST)
long-float-epsilon
= double-float-epsilon
= single-float-epsilon
= 1.110223024625157f-16 (KCL/AOS)
6.938893903907228f-18 (KCL/VAX)
5.5511151231257827f-17 (KCL/SUN and KCL/UST)
long-float-negative-epsilon
= double-float-negative-epsilon
= single-float-negative-epsilon
= 6.938893903907228f-18 (KCL/AOS)
6.938893903907228f-18 (KCL/VAX)
5.5511151231257827f-17 (KCL/SUN and KCL/UST)
pi = 3.141592653589793
See Chapter 12 of the Common Lisp Reference Manual for their meanings.